A formerly homeless man took ownership of a $1.5 million brownstone from an 84-year-old woman in an elaborate scheme involving multiple aliases, phony 911 calls and a forged city deed, according to court papers.

Henry Rothenberg, who also goes by the names Henrique Nixon and Henry Yisrael, was caught after homeowners Jacqueline Hembrick, 84, and her son Kevin Hembrick, 62, called police when he banged on their door and tried to throw them out of their longtime Harlem home last fall.

Now the Department of Finance is investigating the shady character who lives in an SRO on West 145th Street.

“He got a bunch of alias: Henrique Nixon, Henry Israel, Rothenberg,” an SRO neighbor told The Post. “He always carries a briefcase, wears a suit and tie but he ain’t got s–t going on. We all call him Mr. Wall Street. I know him from the shelter,” the neighbor said.

Rothenberg successfully transferred title to the three-story home on Convent Avenue in 2013 by claiming it was left to Alexis Stanton, purportedly the “sole survivor” of Jacqueline’s later mother, Helena Gomillion, according to court papers filed by the Hembricks.

In fact, the Hembricks lawyer Mark Gray believes Stanton doesn’t even exist. In a Manhattan Surrogate’s Court suit filed to nix the deed transfer, Gray says Gomillion’s two immediate survivors are her daughter Jacqueline and a 90-year-old son who lives in The Bronx.

After Rothenberg pulled off the scam last July, the Hembricks started getting visits from cops responding to mysterious 911 calls reporting a home invasion.

They had also received paperwork from the Department of Finance about faulty filings related to the property, which had been in their family since 1945.

The suit says the department also notified whoever applied for the deed transfer that there were particular defects in the paperwork, but the mistakes were eventually fixed and the former bum was suddenly a millionaire.

A spokeswoman for the Department of Finance said the scheme is so common that the agency has arrested 10 fraudsters like Rothenberg in the past year.

Rothenberg did not answer the buzzer at his real West 145th Street pad.

Finance Commissioner Jacque Jiha told The Post his agency has implemented “a number of changes in our recording process as a deterrent” including “introducing a bill in the state legislature to better protect homeowners from these criminals.”